I bought a MSG91SS or PTR91 Super Sniper a few months ago. It has the 20in fluted Thompson Match barrel, and is fully floated. The top rail is welded on and there are no iron sights. For optics I went with the Nikon M308. This scope is clear, has accurate windage and elevation, and draws a lot of light at night. The mount sucked though. It is a one piece aluminum that is then clamped on with 2 moving pieces at the base. There is no way to remove your scope and remount it without having to sight your gun in again. I replaced those mounts with Leupold Steel QD rings. Solid and simple. It shot great, and I had consistent groups under 1 MOA with Remington 168gr Match. But it would still push me off target after every shot. I wanted to be able to watch my rounds impact or at least stay on target. So I added the buffer technologies poly buffer, and it helped. Having the bolt slam into the poly bushing instead of the steel made a noticeable improvement. But I still wanted more control, and the trigger needed work. Buffer Technologies Recoil Buffer HK 91 93 G3 Polyurethane I then sent the trigger off to Bill Springfield in Colorado. I can not say enough good things about this guy. He worked very fast, cheap price, and the improvement is night and day. The squeeze feels about 3.5 lbs, the reset is about 2mm. If I had more PTR's I would be sending all of the triggers off to get fixed. Bill Springfield - www.TriggerWork.net The standard trigger housing again sucked. Its skinny and plastic. I replaced it with a clipped and pinned steel SEF housing from RTG. I then added the Ergo grip from HKParts | Heckler & Koch Genuine Parts - HKPARTS.NET . Again a huge improvement over the stock set up. Gun Parts - RTG International Surplus Gun Parts and Militaria I sent the barrel off to Mike at Arizona Response Systems. Arizona Response Systems, LLC. Home Page. Products & Services for the Armed Professional. . Communication was slow and the work took some time. But the result was a threaded and tapered muzzle with a JP recoil eliminator mounted. The JP takes all the push out of the gun. At night time there is almost no muzzle flash. Someday Id like to replace it with a suppressor, but until then it does its job well. Mark did an amazing job and despite the barrel coming back smelling like it smoked a pack of cigarettes a day, I would gladly send guns to him again. Excellent work. Arizona Response Systems, LLC. Home Page. Products & Services for the Armed Professional. The result is the best rifle Ive ever owned. Accurate, fast, reliable and comfortable to shoot. I have put a few hundred rounds though it with ZERO malfunctions. Ive also got a Burris Fastfire mounted on a 45 deg and zeroed at 50 yards. I keep the Nikon zeroed at 100. I added a cheek piece to the PRS stock for a little added comfort. Its not needed, but make for a great rest when laying behind this thing for a day of shooting. Ive only got to do a little testing since Ive had it all back and put together. Still getting under 1 MOA with the Remington but Im trying 10 different factory loads in it. Ill post the results when Im done. Looking like the Silver State Armory 168gr OTM may win though. Its giving me 1/2 MOA 5 shot groups.